Mine roof supports



G. H. COTTERILL MINE ROOF SUPPORTS Jan. 13, 1970 4 Sheets-Sheet 1 Filed June 21, 1968 INVENTOR: GERALD .H. COTTERI'LL Jan. 13, 1970 G. H. COTTERILL MINE ROOF SUPPORTS 4 Sheets-Sheet 2 Filed June 21, 1968 INVENTOR; GERAL D H. CoTTE R LL Ave. 3

1970 GJH COT TERILL 3,488,966

' MINE-ROOF SUPPORTS Filed June 21, 1968 4 5 t s 5 INVENTOR:

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1970 G. H. COTTERILL MINE ROOF SUPPORTS 4 Sheets-Sheet 4 led June 21, 1968 mvmon; GERALD 'TTER LL.

BY g t Aways.

United States Patent 3,488,966 MINE ROOF SUPPORTS Gerald Herbert Cotterill, Pinxton, England, asslgnor to Gullick Limited, Wigan, England, a British company Filed June 21, 1968, Ser. No. 739,045 Claims priority, application Great Britain, July 28, 1967, 34,721/ 67 Int. Cl. E21d 1.5/44, 15/48; B61] 11/02 US. Cl. 6145 6 Claims ABSTRACT OF THE DISCLOSURE A mine roof support comprises a box-like base or floorengaging member and an inverted box-like roof-engaging member mated together telescopically so as to form an extensible and contractable roof-supporting structure. At least one hydraulic leg or jack is positioned between said members for setting the roof-supporting structure in a roof-supporting condition, said leg or jack having pivotal or articulated locations on said members. A clearance is provided between the members to permit a limited amount of unrestrained tilting of the leg or jack in its location on the members. The extensible and contractable roof-supporting structure is capable of taking and controlling forces due to convergence and relative lateral movement between a mine floor and roof.

This invention is for improvements in or relating to mine roof supports.

In the longwall method of mining coal or other mineral the roof is supported during the winding sequence by support units known as chocks. Following removal of the mineral from the face the chocks are released from between floor and roof, advanced towards the face and then re-set between floor and roof to support the newly exposed roof.

During the period when the checks are set between floor and roof what is known as convergence takes place and there is relative lateral movement between the mine roof and floor. Generally the roof moves away from the mineral-bearing face and towards the floor.

Heretofore such chocks have comprised a base member, a roof-engaging member and one or more hydraulic jacks or legs between said members. With such an arrangement control of the aforementioned lateral movement of the roof, relative to the floor, has been through the hydraulic jacks or legs and the resultant bending moment on the jacks has in time resulted in damage or bending thereof. As a consequence of this damage or bending it has sometimes been necessary to resort to excavation to release the chock from between floor and roof, the hydraulic jacks or legs having been rendered inelfective.

According to the present invention there is provided a self-advancing mine roof support comprising a roofengaging member and a floor-engaging member each in the form of a box, having elongated sides and a top closure means and a bottom closure means respectively rigid with said sides, and positioned telescopically one well within the other, at least one hydraulic jack positioned within said structure for adjusting the height thereof and having its upper and lower ends bearing respectively against articulating locations on said top closure means and bottom closure means, there being a substantial clearance between the two members where they are positioned one within the other whereby a limited amount of unrestrained relative tilting of the members and of the jack, in its said articulating locations, can take place, thelateral dimensions of the roof-engaging member and the floor-engaging member being large as compared to the diameter of the jack, said roof-engaging and floor engaging members and said jack forming together a roofsupporting structure capable of taking and controlling forces due to convergence and relative lateral movement between a mine floor and roof, and a pressure-fluid ram means housed in said roof-supporting structure for advancing the support.

The hydraulic jack in the arrangement above set forth is vertically load-bearing whilst the lateral loading is distributed in the roof and floor-engaging member relationship, said members being designed to take and control excessive tilting of the jack in or on its articulating locations on said members, due to convergence and relative lateral movement between the mine floor and roof.

The support may be of the Walking type comprising two units, the pressure-fluid ram means for advancing the support comprising a hydraulic ram having its piston connected to one of said units and its cylinder connected to the other. With such an arrangement one of said units alternately serves as an abutment or anchorage for the advancement of the other when the latter is temporarily released from between floor and roof. Alternatively, the support may have a hydraulic ram which utilizes a coal face conveyor as an anchorage for advancing the support whilst the latter is temporarily released from between floor and roof.

The roof support unit may, by the addition of packing pieces or by variation in the length of the extending means, be adapted to mine workings of various thicknesses. Similarly, by the extension of the base or floorengaging member in the direction of length of the coal face, the units may be used on inclined seam workings.

The telescopically mated roof-engaging and floor'engaging members may be of various different cross-sections which can be readily produced and need not necessarily be rectangular or cylindrical although such cross-sections have been found particularly convenient.

By the provision of an access means at the leading side of the chock the hydraulic jack or prop or other extending means may be readily removed if required.

A mechanical stop, which may be yielding (e.g. of wood) may be provided within the chock to prevent damage to the extending means in the event of a failure.

Preferably there is also provided in the chock means for aligning the two telescopically mated roof-engaging and floor-engaging members. Such aligning means may be used during the collapse or lowering of the chock to ensure free movement between said members and/or to set the roof-engaging member in an attitude leaning towards the mineral face. The subsequent movement created by roof convergence will then be well within the allowance provided for between the telescopically mated roof and floor-engaging members.

Some particular embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a side elevation of one form of chock according to the invention,

FIGURE 2 is a front elevation of the chock shown in FIGURE 1,

FIGURE 3 is a front elevation of a chock similar to that shown in FIGURES 1 and 2 but modified to adapt it for inclined seams,

FIGURE 4 is a side elevation of a further form of the invention applied to a two-element type of chock or support,

FIGURES 5 and 6 are side elevations showing an application of the invention to a chock of the walking type, and

FIGURE 7 is a side elevation showing the roof and floor aligning means.

Referring first to the embodiment shown in FIGURES 1 and 2, the chock has a base or floor-engaging member 10 and a roof-engaging member 11. I

The members 10 and 11 are of rectangular box-like form open at the top and bottom respectively and the member 11 telescopes into the member 10.

Two hydraulic jacks 12 are provided, in the telescopic structure 10, 11, for raising the roof-engaging member 11 in a vertical direction relatively to the base or floorengaging member 10. The jacks 12 may be made dubleacting so that they not only serve to raise the member 11 to set the chock between floor and roof but also serve to lower said member positively when the chock is to be advanced.

The chock is of the self-advancing type and for this purpose is provided with an advancing ram 13 having its cylinder fixed to the chock and its piston adapted for connection by means of a clevis 14 to the coal face conveyor C. By retracting the ram 13 the chock is advanced towards the conveyor in the well known way.

A skirt or elastic sealing ring is provided at 15 to exclude material from the gap 16 between the members 10 and 11.

The hydraulic jacks 12 are pivotally supported at their ends by means of convex/concave seating devices 17 and 18.

The gap or clearance 16 between the members 10 and 11 provides for a limited amount of unrestrained tilting of the jacks or legs 12 on their pivotal or articulated locations 17 and 18.

A stop 19 is provided on the bottom of the member 10 to halt the member 11 to prevent damage to the prop 12 in the event of failure thereof. In other words, the stop 19 will halt the member 11 before the prop 12 has been completely collapsed and will thereby relieve the prop 12 of load. Preferably the stop 19 has a limited degree of yield and for that purpose may be made of a material able to give slightly under load, e.g. wood.

The hydraulic jacks 12 and ram 13 are controlled by valve gear 20.

As shown in FIGURE 2, openings 21 and 22 may be provided in the members 10 and 11 to give access to the hydraulic jacks 12.

When the chock is intended for use in inclined seams the base or floor-engaging member is preferably provided with extensions 23, to stabilize chock, as shown in FIG- URE 3.

The front and rear units of the support shown in FIGURE 4 are similar to the chock already described with reference to FIGURES 1 and 2 and where applicable like reference numerals have been used to designate like parts. The rear unit 24 of the support shown in FIG- URE 4 is attached to the front unit 25 by tie-bars, means 26 pivotally connected to the base of the rear unit and the base of the forward unit at 27 and 28. A relay or extension bar 29 serves to connect the piston of the advancing ram 13 to the coal face conveyor C. Packing or vertical extension pieces 30 are provided on the upper members 11 of the rear and forward units, a canopy 31 and roof-bar 32 of the support being mounted respectively on these packing pieces. Preferably these mountings (see FIGURE 7) are of the concave/convex type as indicated at 33/34 and 35/36 so as to allow alignment to the roof to take place. Similar mountings may be provided between the support unit or units and the floor.

The mode of operation of the walking support shown in FIGURES and 6 is as follows:

After a cut of the coal face has been made the forward unit of the support is temporarily released from between floor and roof and advanced by extending the ram 13 using the rear element of the support as an abutment. The rear element is then temporarily released from between floor and roof and advanced up to the forward element by retracting the ram 13 and using the forward element, which has been re-secured between floor and roof, as an anchorage.

Finally, the rear element is re-secured between floor and roof.

The Weight of the superstructure of the chocks above described greatly assists in the lowering thereof.

The support can be built up of small standard interchangeable units or elements.

Inasmuch as three sides of the chock have no entrances the problem of the chock being fouled by dirt from the gob is avoided.

A ram 40 (see FIGURE 3) may be provided for the alignment or relative angular adjustment of the two units 10 and 11.

It will be appreciated from the above-described examples of the invention that the restriction of lateral movement of the roof-engaging member due to convergence is between the base 10 and the extendable member 11, whilst the extending means (the jacks 12) are always axially loaded and are not subjected to a bending moment.

I claim:

1. A self-advancing mine roof support comprising a roof-engaging member and a floor-engaging member, each in the form of a box having elongated sides and a top closure means and a bottom closure means respectively rigid with said sides and positioned telescopically one Within the other, at least one hydraulic jack positioned within said structure for adjusting the height thereof,

articulating means respectively between the upper and lower ends of said jacks and said top closure means and bottom closure means, there being a substantial clearance between the two members where they are positioned one within the other whereby a limited amount of unrestrained relative tilting of the members and of the jack through said articulating means can take place, the lateral dimensions of the roof-engaging member and the floor-engaging member being large as compared to the diameter of the jack, said roof-engaging and floor-engaging members and said jack forming together a roof-supporting structure capable of taking and controlling forces due to convergence and relative lateral movement between a mine floor and roof, and a pressure-fluid ram means housed in said roof-supporting structure for advancing the support.

2. A mine roof support as claimed in claim 1 wherein said articulating means include internal concave seatings on the top closure means and the bottom closure means, and upper and lower convex ends of the jack and respectively engaged in said seatings.

3. A mine roof support as claimed in claim 1 wherein an elastic sealing member is provided on the side walls of the roof-engaging member and bears on an upper edge of the side walls of the floor-engaging member so as to seal the entrance to the clearance between said members.

4. A mine roof support as claimed in claim 1 wherein said unrestrained relative tilting of the roof and floorengaging members is limited by a lower edge of a wall of the roof-engaging member coming up against a wall of the floor-engaging member and by an opposite wall of the roof-engaging member coming up against an upper edge of an opposite Wall of the floor-engaging member.

5. A mine roof support as claimed in claim 1 wherein a stop is positioned below the roof-engaging member to limit lowering of said member and thereby prevent dam- 3,309,05 3/ 1967 DaViS-Ratcliffe 61-45 age to the hydraulic jack in the event of a failure of the 3,362,169 1/ 1968 Groetschel 6145 support.

6. A mine roof support as claimed in claim 5 wherein FOREIGN T the stop has a limited degree of yield. 980,581 1/1965 Great m 5 1,061,071 3/1967 Great Br1ta1n. References Ci d 1,092,413 11/ 1960 Germany.

UNITED STATES PATENTS DENNIS L. TAYLOR, Primary Examiner 2,899,800 8/1959 Joy 6 US. Cl. X.R.

3,218,812 11/1965 Wilkenloh 61 45 10 248-357 

